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Right internal thoracic veins

The right internal thoracic veins (also called internal mammary veins) are paired venous channels that accompany the right internal thoracic artery along the posterior surface of the anterior thoracic wall. They drain the anterior intercostal spaces, superior epigastric vein, and musculature of the anterior thoracic wall.

Typically, two venae comitantes run alongside the internal thoracic artery, interconnected by transverse venous channels. They ascend superiorly along the sternum and usually unite as a single trunk near the thoracic inlet before draining into the right brachiocephalic vein. Variations may include persistent paired drainage or accessory tributaries.

These veins play an important role in systemic venous return and collateral circulation. In superior vena cava (SVC) obstruction, the internal thoracic veins form important collateral pathways via the superior and inferior epigastric systems. They are also relevant surgically, as they are encountered during sternotomy, breast reconstruction, and internal thoracic artery graft harvesting.

Synonyms

  • Right internal mammary veins

  • Venae thoracicae internae dextrae

Function

  • Drain anterior thoracic wall and intercostal spaces

  • Provide venous return from superior epigastric and musculophrenic veins

  • Contribute to collateral venous pathways in SVC obstruction

  • Serve as surgical landmarks in cardiothoracic and reconstructive procedures

Tributaries

  • Anterior intercostal veins

  • Superior epigastric vein

  • Musculophrenic vein

  • Small mediastinal and pericardial veins

MRI Appearance

T1-weighted images:

  • Veins appear as flow voids (dark tubular structures) running alongside the internal thoracic artery

  • Surrounded by intermediate-signal soft tissue and hyperintense fat

T2-weighted images:

  • Veins show signal voids, but thrombus may appear as hyperintense depending on stage

  • Helpful for identifying venous patency

STIR:

  • Fat suppression improves visualization of venous course against mediastinal fat

  • Detects perivascular edema or inflammatory change

T1 Fat-Saturated (Pre-contrast):

  • Lumen may show intermediate signal intensity, contrasting with suppressed fat planes

T1 Fat-Saturated Post-Contrast (Gadolinium):

  • Veins enhance homogeneously in venous phase

  • Detects stenosis, thrombosis, or anomalous drainage

MRV (Magnetic Resonance Venography):

  • Provides clear mapping of the right internal thoracic venous system and its connection to the right brachiocephalic vein

  • Useful in collateral circulation evaluation, venous obstruction, and surgical planning

CT Appearance

CT Pre-Contrast:

  • Veins appear as linear soft-tissue densities along the posterior sternum

  • Usually indistinct without contrast

CT Post-Contrast:

  • Veins enhance brightly in venous phase, clearly showing confluence into brachiocephalic vein

  • Helps identify venous variants, obstruction, or thrombosis

CTV (CT Venography):

  • Provides detailed 3D reconstructions of the right internal thoracic veins, their tributaries, and brachiocephalic drainage

  • Essential for evaluating SVC obstruction, collateral pathways, and preoperative mapping

MRI image

Right internal thoracic veins MRI coronal anatomy image -img-00000-00000

CT image

Right Internal Thoracic Veins Anatomy ct axial